The wind triangle.
Your aircraft carries two independent velocity readings. The pitot and compass give the air vector — how fast and in which direction you move through the airmass. The GNSS receiver gives the ground vector — how fast and in which direction you actually move over the earth.
If the two disagree, the difference is not an error. The difference is the wind. That subtraction, drawn as a triangle, is the whole theory:
Circling: wind from the drift.
A basic instrument has no compass, so it cannot draw the triangle directly. It waits for you to thermal. Over one full circle your average velocity through the air is zero — every direction cancels — so whatever net motion the GNSS records over that circle is pure wind. Your circles drift downwind, and the drift is the measurement.
It works, and it is how gliding computers estimated wind for decades. But it has an honest limitation: you only get a fresh number while circling, in that thermal's airmass. Leave on a 40 km glide and you are flying on old data.
Straight flight: a heading source changes everything.
Add a real heading source — a magnetometer-corrected AHRS — plus true airspeed from the pitot, and the triangle closes instantly, on every straight kilometre. The computer subtracts vectors continuously and updates the wind while you glide, not just while you climb.
This is why an AHRS unit is not just an artificial horizon. It upgrades every downstream number: live wind, which feeds speed to fly, which feeds final glide. One sensor, three better decisions.
Or no compass at all.
There is a third way to know where the nose points: watch how the glider moves. Gyros and accelerometers measure every rotation and acceleration; GNSS measures how the velocity over the ground changes. Every turn, every speed change and every bump of turbulence shows up in both, and only the true heading makes the two agree. An estimator that keeps checking that agreement can hold heading and wind with no magnetometer to calibrate and no second antenna to install — best while the glider turns and manoeuvres, least well in long, smooth straight flight.
Solve the same triangle in three dimensions and the leftover gains a vertical component: the rising or sinking of the air itself — a netto vario built so that a horizontal gust does not move it. That is what Atmo does inside the Era. Como funciona o Atmo →
O que o vento faz com o seu planeio final.
Same 15 m standard-class polar as the MacCready article. The tool picks the speed that loses the least altitude over ground — watch how a headwind demands a faster glide and much more height.
Includes a 300 m arrival height. Positive wind = headwind. Still air, MC 0 — a teaching simplification of what your computer solves with live wind and MC.
No seu cockpit.
Watch your wind display after a long straight glide with a heading source, and after ten minutes of circling without one — the difference is the difference between measuring and remembering. It is also why we put a magnetometer and AHRS at the heart of the Navia sensor family.
Vento 3D ao vivo e um smart vario imune a rajadas no Era – sem bússola nem segunda antena.
AD-AHRS with magnetometer — live wind on every straight glide.
Racing flight computer with continuous wind and final glide.
Standalone vario system with circling-drift wind and speed to fly.